Autoloading pistol



May 3, 1949. H. E. sEAGRAx/Es AUTOLOADING 'PISTOL Mom, mm, .E bm. l

May 3, 1949. H. E. sEAGRAvEs AUTLOADING PISTOL 4 Sheets-Sheet 2 FiledSept. 2, 1944 IN V EN TOR.

May 3, 1949.

H. E. SEAGRAVES AUTOLOADING PI S TOL 4 shets-sheet 5 Filed Sept. 2, 1944\NVENTOR @M5 E s y m @25:2 :2:: t i ai H Wl, m. E .IQ @S E .IQ KQ ..l QQQQ i: f

IMaly 3, 1949.

H. E. SEAGRAVES AUTOLOADING PISTOL 4 Sheets-Sheet 4 Filed Sept 2,1944

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for admitting barrel gas to the space.

Patented May 3, 1949 UNITED STATES PATENT @FFICE 4 Claims.

This invention relates to pistols and has for its object the provisionof an improved autoloading gas-operated pistol. The improved pistol ofthe invention comprises a receiver having a breech bolt therein, abarrel connected to the receiver which is oblong in cross-section with aspace in the upper part of the barrel for a gas piston operativelyconnected to the breech bolt, and a grip member for the barrel andreceiver with a space in the grip thereof for a cartridge magazine. Thepistol of the invention is characterized by the fact that its mass suchas the receiver, breech bolt and barrel are xed at the instant of firingand accordingly do not move independently of other parts of the pistol.

The autoloading pistols proposed and constructed heretofore, bothgas-operated and otherwise, have had such a preponderance of weightbelow the bore plane (a horizontal plane through the center of the borewhen the pistol is in its horizontal firing position) that ring causes aviolent upward flip of the muzzle. This, of course, is accentuated bythe position of the gri-p which results in an upward force component.The upward flip of the muzzle contributes to inaccurate shooting andresults in sighting complications when changing from one distance toanother. The preponderance of weight below the bore plane has been dueto the arrangement of the essential elements below the bore plane andthe proportioning of the various parts. The pistol is peculiar amongguns for the reason that it must have maximum low weight limits,regardless of the caliber, it is semi-automatic, firing once each timethe trigger is pressed, it must have a grip below the bore to permitsighting, and it must be held in the outstretched hand. The hand is veryyieldable under the terric impact of the explosion, and actually haslittle influence on the upward flip of the muzzle at the instant offiring, while the bullet is in the barrel.

In one of its main aspects, the ivention provides an autoloading pistolwith such :a proportioning and arrangement of the supporting structureand operating mechanism, both below and above the bore plane, that thecenter of mass is at or above the bore plane and the upward ip of themuzzle is substantially reduced. The invention provides an improvedbarrel which is narrow and deep in cross-section (oblong) withgas-operated means in a space above the bore for operating the breechbolt, Which has a preponderance of weight 'above the bore plane,together with means The barrel and receiver are preferably unitary andmay advantagously be integral as when formed of a single piece of metal.The barrel-receiver is detachably connected to a grip member comprisingspace and mounting means for the trigger, sear, hammer and magazine. Thegrip member is constructed as light as possible and may be made of steelin which case it is skeletonized to reduce weight in the lower part ofthe pistol. The grip member may also be formed of a molded plasticmaterial, or oi magnesium alloy, `aluminum or aluminum alloy castings.These light weight molded and cast materials not only simplifyconstruction but greatly reduce the weight in the lower part of thepistol.

One of the features of the invention is the provision of a pistol with afixed barrel and receiver with no exterior moving parts in the automaticsection. In one embodiment of the invention means are `arranged at therear end of the receiver for the manual operation of the breech bolt,and the sides and top of the receiver are free of exterior moving parts,the only opening in the receiver being for ejecting the empty cartridgecases. This is an important feature in view of the fact that thereceiver and barrel are iixed with respect to each other and the gripmember.

The invention, in another of its aspects, provides a very simple andpositive sear release comprising a trigger rod which is disengaged fromthe sear by the backward movement of the hammer and reengaged with thesear after the hammer is cocked.

Another feature of the invention is an improved means whichautomatically locks the hammer each time it is cocked by means of asafety sear and which is operated by a linger release on the forwardface of the grip. This construction provides a safety feature withoutintroducing any moving element in the heel of the grip. Devices mountedin the heel of the grip which are pressed in by the palm of the hand torelease the hammer are very annoying to target shooters who prefer aiixed heel against the hand.

Still another feature of the invention is the provision of a very simplemechanism for holding the breech bolt in its open position when themagazine is empty and which automatically closes the breech bolt when amagazine with at least one cartridge is inserted into the grip. lApivoted spring-pressed member on one side of the receiver engages thebreech bolt each time the breech bolt moves rearward with the magazineempty or removed. Means on a side of the magazine actuated by thecartridges prevents the spring-pressed member from engaging the breechbolt when a cartridge is in the magazine. rlhis permits target shooters,firing slow lire, to have the breech automatically opened and left openafter each shot.

These and other novel features of the invention will be betterunderstood after considering the following discussion taken inconjunction with the accompanying drawings in which Fig. 1 is a sideView, partly in section, of a pistol embodying the invention;

Figs. 2, 3, 4 and 5 are Views along lines 2-2, 3-3, 4-4 and 5-5respectively of Fig. 1;

Fig. 6 is a View of the bolt of Fig. 1 from above;

Fig. 6A is a fragmentary View from below of the slide;

Fig. 7 is a side View of the pistol of Fig. 1 with internal partsexposed;

Fig. 10 is a fragmentary exterior view of the rear end of the pistol ofFig. '7;

y Figs. 8, 9, 11 and 12 are views along lines 8 8, F43', II-II and I2-l2respectively of Figs. '7 and Fig. 131s a side View of another embodimentof the' invention;

Figs. 14, 15, and 16 are views along lines I4-I4, |'5-`I5 and IIE-I6respectively of Fig. i3;

Fig. 17 is a fragmentary view of the rear end of the pistol of Fig. 13with interior parts exposed;

Figs, 18 and 19 are views along lines Iii-I8 and I`9-I9 respectively ofFig. 17;

I3Fig. 20 is a View from above of the bolt of Fig.

Fig. 21 is a side View, partly in section, of the barrel-'receiverportion of the pistol of Fig. 13;

n Fig. 22 is a fragmentary side View, partly in section, of stillanother pistol embodying the inventio'n;

Figs. 23 and 211 are views along lines 23-243 and 24-24 respectively ofFig. 22;

Fig. 25 is a fragmentary side view oi Fig. 22 and 2G is a view alongrline Ztl-26 of Fig. 24 with the' bolt moved rearward.

The' pistols illustrated in the drawings comprise three mainnparts, abarrel B, a receiver R and a member G. The barrel and receiver mergeintoAeach other at the rear end of the cartridge chamberrand may beconnected 'together in any suitable' way as a unitary structure. Asshown in the drawings -they are integral having been formed by simplemechanical operations from a single bar of steel or equivalent metal.The integral barrel-receiver is removably attached to the grip memberand the barrel is of oblong cross- Sectional shape having substantiallyiiat or Slightly curved sides with a preponderance of its Weight abovethe bore place.

The `pistol of Figs. 1 to 12 has a barrel-receiver with a longitudinalspace extending from end to endythe space I in the receiver beingsubstantially rectangular and the space in the barrel being a cylinder2. The slide 3 is reciprocably mounted inthe space with the piston 4 inthe cylinder 2 andthe cam part 5 in space I is rectangular at the topand partly cylindrical at the bottom. The forward end of the cylinder isclosed with a screw plug 6 and the gas port I connects the cylinder 2with the bore. The port I is close to the end of the bore and is easilyaccessible for cleaning. 'A'slot 8 in the top of the barrel receives thesight 9,- Whi'ch is slidable up and down against the plug U: The sightis secured in an adjustable position by the locking plug ID which bearsagainst the sight. Advantageously, the slot II for a screwdriver in plug6 receives the depending part of the sight and is accordingly preventedfrom turning. The plugs 6 and I0 not only securely close the end ofcylinder 2 but provide means for elevating or lowering the iront sightand securing it in the desired position. The slide 3 has aneccentrically disposed 4cylindrical hole I2 for housing the actionspring I3 which bears against the piston at one end and' the plate I4 onthe pilot rod I5 on the opposite end. Piate I6 bears against theprojecting lug I5 on the frame 4l of G. The cylindrical chamber 23'formed in line with the bore receives the cylindrical breech bolt 2|which has therein the firing pin 22 and ring pin spring 23. Thelbreechhbolt has an upwardly extending turning lug 24 which engages withthe rectangular slot I8 and helical cam slot 25 in the cam part 5 oi theslide (Fig. 6). The bolt has a springpressed-'pinetype ejector 28,extractor 29, and a. cam slot 35i for engaging the lug 3| on the 4iiringpin, two locking lugs 32 and 33 on one side, and a locking lug 34 on theopposite side. AThe lugs 32 and 33 travel in the guide groove 33 duringreciprocationoi the bolt and enter locking slots 3i and 38 when the boltis turned to its locked position. Lug 3A travels in guide slot 39 andenters the ejection opening 40, bearing against the rear edge thereofwhen the bolt is turned to its locked position. The side grip plates l2and are attached to the slide for manual operation of the bolt and thesereciprocate with the slide, in the guide slots 44 and 45. n

The under portion oi the barrel has a depending wedge-shaped block 46.The barrel-receiver and assembled elements' just described areremovablyattached to the grip member G in a very simple manner. The projectinglug li on the heel of the grip member frame 4'! fits snugly into thespace I and the block 4@ lits snugly in a wedge-shaped slot in the frontend of frame 41 (Fig. 8). To remove the barrel-receiver from the gripmember, the cotter pin 48 is pushed out and the barrel-receiver may bepulled forward. The lug I6 secures the barrel-receiver at the rear andblock 46 secures it at the forward end.

The grip member frame 4'! may be formed of steel, in which case it iscut away as much as possible to reduce its Weight, or it may be formedoi alloys of aluminum or magnesium or a plastic material as will be morefully described hereinafter. The frame illustrated has cut out opensides which are covered with the wood grips 49 and 5G secured inposition by screws 5I and '52. The central part has a chamber 53 forreceiving the box magazine 54 which is held in position by the catch 55.The hammer is pivoted on the screw 5'? and is driven by the tension coilspring 58 secured to the frame by screw Sii and to the hammer by pin El.The hammer has a cam shoulder 62 projecting to the right and a dependinglug E3. The' trigger-operated sear 64 is pivote'd on the screw-t5, hasan upward extension G6 for engaging the notch 5'! on the trigger rod 6Band a shoulder 39 for engaging the hammer notch it. The scarcompression'spring II is secured in a recess I2 in the frame and ts overa nipple 'I3 o-n the sear which holds it in position thereon'.

As best shown in Figs'. 3 and 11, a safety sear 'I4 is alsol pivoted onpin 65 and it has a shoulder 'I5 for engaging the hammer in the samemanner als sear 6'4. The coil compression spring 15'io'i`- sear I4 issecuri'eclv in the recess 'Hin the frame and fits over the nipple i8 onthe safety sear which secures it in position thereon. The safety searalways catches the hammer in the same manner as sear Sil. The safetysear is operated by a release button S so arranged as to be pressedinward by the large or second finger, and the hammer cannot be releaseduntil button 80 is pushed in. Button 80 is connected to a U-shaped bar8| which slides in a slot 32 inside the grip |39 (Fig. 9) and engages aslot 33 in the lower end of the safety sear. The flat spring 3d isattached to the frame by screws 85 and Si@ and the upper forked end 8lthereof ts into a slot 08 in the button 80 normally forcing the buttonto the projecting position shown in the drawings with the bar 3| out ofbearing contact with the slot 83 in the safety sear. By pressing thebutton 33 inward, the safety sear is moved out of contact with notch 10and the hammer may be released by pulling the trigger. The lower part 30of the spring 8f3 bears against the magazine catch 55 and holds it inits locking position (Fig. l). It will thus be seen that spring 83performs a dual function. Catch 55 can only be released by pushing itforward, an advantage when the gun is used in the brush.

As shown in Figs. 1 and 4, thel trigger 9| is pivoted on screw 32 andhas a bifurcated upward lever arm 913 with the trigger rod 33 thereinand pivoted thereto by the pin 05. The trigger rod is urged to the rearby the coil spring which may be adjusted for tension by the screw 91.The spring 96 not only sets the trigger rod in position for actuatingthe sear, but it regulates the trigger pull and this may be varied byscrew Si?. The coil spring 93 around the screw 32 has one arm 33 bearingagainst the frame and another arm 33 hooked over the top of the triggerrod. As thus arranged the spring turns the trigger rod counterclockwiseso that the notch el therein will snap down over the sear top 66 when inproper position. It will be seen in Figs. 1, 2 and 3 that the triggerrod has a U-shaped portion permitting it to operate around the magazineand inside the grip 50.

Referring to Fig. 1, it will be seen that the f hammer is pushedbackward by the bolt beyond the cocked position of Fig. 7 and that thecam shoulder e2 has lifted the trigger rod 08 upward disengaging thenotch 61 from the top 33 of the sear. The sear 6d is accordingly free toengage the hammer whether the trigger be held or released. When the bolttravels forward the hammer follows it until it is caught by both searsas shown in Fig. 7. (Safety Isear Hi has no connection with thetrigger.) hammer drops the cam shoulder 32 permitting the trigger rod torest on the top (i6 of the sear, if the trigger be held, and the notchSl to drop over the top 60 if the trigger be released. In any event,when the trigger is released and the hammer is cocked, the notch (ilwill always engage the top 65 of sear 04.

The safety bar |02 pivoted on screw 00 has a hub |03 which cooperateswith bushing H03 to center the Ispring 58 on the screw (Fig. 12). Thesafety bar has a channel |35 and a flat end H06 (Fig. 1). In the safeposition shown in Fig. 7, the channel |35 straddles the lug 63 of thehammer preventing it from moving regardless of the position of the searsand the end |06 engages both sears blocking them from movement and thehammer is triple locked. In the non-'safe position of Fig. 1, the safetybar is pushed down out of engagement with the hammer and the sears. Thenotch |07 in the sears permits them to be This movement of the turnedand to clear the at end |06 when the safety bar is in the position ofFig. 1. The safety bar is operated by an exterior thumb button |08 whichis connected thereto by screw |03 through a slot 0 in the side of theframe 41. As best shown in Fig. 1l, the safety button has two flattenedears which bear against the side of the frame by spring action. Theframe has four shallow grooves lll, ||2, ||3 and I|4 in which the headsH5 and l i6 on the inner end surfaces of the ears make engagement. Inthe safe position of Fig. 11, beads ||5 and ||6 are in grooves l l andi3. In the non-safe position, the beads l i5 and i i3 will engage beadsl I2 and l I4 respectively. The button |08 cannot be set in the Isafeposition unless the hammer is cocked.

As shown in Fig. 1, the bolt is ready to start forward under the drivingaction of spring I3. The bolt is pulled forward by the lug 24 and isprevented from turning during its longitudinal travel by the lugs 32 and33 traveling in guide 36 and lug 33 traveling in guide 39. Fig. 6 showsthe bolt as it reaches the end of its forward stroke with the cartridgepushed into the barrel chamber. The bolt is in its unlocked position andis free to slide rearward. Further forward movement of the slide 3 willresult in the cam 25 turning the bolt counterclockwise to its lockedposition with the lugs 32 and 33 in the locking slots 3l and 33 (Fig. 1)and the lug 36 in the ejection opening 10. After closing the bolt, theslide continues to travel forward a short distance, say aroundthree-eighths of an inch, the lug 24 entering the rectangular slot I8which locks the bolt in position preventing it from turning. The bolt isnow locked with three lugs 32, 33 and 34 and cannot turn.

The lug 3i on the firing pin also travels in groove 3G and is therebyprevented from turning with the bolt. As shown in Figs. 1 and 6, thefiring pin is held to a rearward position beyond the reach of acartridge by the lug 3| bearing against the end of the bolt. When thebolt is turned counterclockwise to the locked position the lug 3|assumes a position in front of cam 30 and the ring pin may be drivenforward by the hammer into contact with the cartridge except when thebolt is locked.

When a cartridge is red and the bullet passes beyond gas port l, the gasrushes into the cylinder 2 and drives the slide 3 rearward. (Fig. 22shows a piston in the firing position.) The slide travels rearward aboutthree-eighths of an inch, the length of rectangular slot i8, withoutacting upon the bolt lug 24. rIhe forward inclined face in cam 25strikes the lug 2li and turns the bolt clockwise to its unlockedposition Shown in Fig. 6. The momentum of the slide in cooperation withthe residual gas pressure, carries the bolt to the rear as shown in Fig.l ejecting the empty cartridge case. A fresh cartridge rises to theposition shown in Fig. 1 and is ready to be pushed into the chamber ofthe barrel on the return of the bolt.

The pistol shown in Figs. 1 to 12 has a bore of about .35 caliber andthe barrel is ve and fiveeighths inches in length. This pistol may beprovided with a bolt catch similar to that of Fig. 22 or with a hammerspring similar to that of Fig. 17 if desired.

The spring of Fig. 1 is especially important in pistols constructed forlong cartridges because it permits the full use of the grip for themagazine and does not make the grip unduly wide and cumbersome.Moreover, the spring is close to the bore eliminates weight inthe `lowerpart of 'grip `iaie'emk'ie'.

*rnefpistei illustrated in Figs. 13 to 21 comprises -blrrel-receiverB-#Rf`slidably attached to the rip member Cf-in a manner similar to'that 0f Figc-1.v The .grip member is formed by casting or molding-andthe supporting frame |20 is a unitary structure with all of the largecavities and eiftferior 'shapelforni'e'd therein by the casting. ormolding operation; It may be cast of aluminum orfiiignesium alloy orformed of a molded plastic materialsuch` as Toollte.

Als-shown' in Fig. 21, the barrel-receiver has a cylindrieallspace' I2bored therethrough and the slide |22 is ln theform of `a cylindricalpiston with an eccentric hole |23 therein for receiving the factionspring |24 andpilot rodi |25. The rear end of .space-HI is closed by thecylindrical projction |21 on theframe` |20 and the discl ttachedtorod|25 bears against projection |21 aidhelps maintain tlie rod in position.The for- Ward'eiid'of cylinder |2| is closed by screw plug |25.`

`Gas: from the bore is admitted to cylinder |2| throughvori'fice |30which is bored in a removable plug 3| fitted snugly in a transverse holethrough the barrel between the bore and the cylinder l2 l. The plug is'providedwith an ear |32 which fits atslot' inl the barrel insuringproper positioning of ythe plug.A The plug is held in position by thescrew |33 and may easily be removed for cleaning. The slide |22 has adepending lug |34 which engages the helical cam 'slot |35 in the breechbolt |35. The boltis reciprocably mounted in a cylindrical space |31 inthe receiver andin line 'with the bore. As best shown in Fig. 19, themetal between cylinders |2| and |31 is cut out to form the guideway |38in which lug |34 travels and.l the slide is prevented from turning. Theprojection |40 on the firing pin |4| and the locking lugs V|42 and v|43travel in the guideway during'reciprocation of the bolt. The ring pinhas 'aspiring |44 for holding it rearward. As shown in Figs. 19 and 20,the bolt is in its locked positionfwitli lugs in locking recesses |45and'll and the 1ug |34`is"in the rectangular part |41 of .thecomplots-|35 `and the bolt is prevented from turning. The turning of thebolt has setthe recessed part of'cam |49 infront of projection |40 onthe firing pin' and the' firing pin is free .tobe driven .forward by thehammer.

VAs shown in Fig. 21, the slide `has moved rearward andthe lug |34 hasturnedthe bolt clockwise toits unlocked position. The slide'and boltarefnow ready to travel rearward under the pressure fof the gas fromIthe bore. The turn of the boltdur'ing the unlocking causes theprojection .|40 to'move the ring pin rearward by the engagement with thecam slot` |49 andthe firing pin cannot contact cartridge. The'rearwardtravel of the slide `and bolt compresses the action spring |24 whichreturns the same to their forwardv positions.I and locks the bolt. Thislocking is done by lug |34 striking the forward helical face of cam slot|35resulting in thebolt being turned counterclockwise to the positionshown in Fig. 20. rlhe .bolt `has an ejector (not shown) similar to thatof Fig. 1 andan extractor le!) which enters afvclearance recess insidecylinder |31 on the rearward travel of the bolt.

The bolt is operated manually bythe ribbed plates |55 and |56 whichtravel the length of slide travel |22 in `recesses |51 and |58 onopposite sides of theffknarrel,A l Plate V|55 hasan integralprojectlngbar 460 which is inserted through a long narrow slot |6| onrthe left side of the barrel,` through a short rectangular slot |62 inthe slide, and through another long narrow slot |63 on the right side ofthe barrel. The plate |56' butts against the end of bar |60 and issecured thereto by sc-rews |64 and |65. To operate the breech boltmanually, the plates are gripped between the thumb and fore-finger andare pulled rearward until the slide and bolt reach the end of theirstroke. 1f the plates are released the action spring drives the slideand bolt forward to the locked firing position.

The pistol of Fig. 13 has a sear and trigger mechanism similar to thatof Fig. l but the hammer is driven by a compression spring |51 in thegripwhich connects to the hammer |68 by Vrod |09. I may use with thepistol of Fig. 13 a. safety seaiand hammer spring similar to 'those ofFig. l and a bolt catch similar to that of Fig. 22.

As shown in Figs. 17, 18 and 19', the safety mechanism comprises a pushbutton formed of two parts |1| and |12 which are connected to gether byscrew |13. Both parts have square ends which iit into square holes onthe Opposite sides of the frame |20 and are, accordingly, prevented fromturning. Part |1| has a slot |141connecting with two hemisphcricalrecesses |15 and |16 in which the plug |11 is pressed by the coil spring|18 held in position in the frame by'screw |80. Part |12 has an upwardextending bar |8| which, when in the same position shown in Figs. 18 and19,A blocks the hammer preventing it from moving'towards the firing pin,and anangularly disposed depending bar |82 which blocks the searpreventing it from releasing the hammer. If button |1| be pushed inward,the plug |11 backs out-of recess |16, travels through slot |14 and snapsinto recess |15 securing button |1| in the non-safe posi-tion flush withthe side of the frame l2 Simultaneously button |12 projects to the rightand bars |8| and |82 `enter the spaces |83 and 34 to the right side orthe hammer and scar releasing them' and permitting the trigger rod |85to operate the sear |85 and release the hammer. The safety mechanism ofFigs. 13 to 21has several positive operating advantages in a pistol. Forexample, in the safe position, button |1| is in the way of the shootersthumb and no time will be wasted in trying to re when the safety is setin the non-firing position. When in the nonsafe or firing position,button |12 projects to the right where it is easily seen even when thepistol is in a holster. Moreover, the safety member cannot be set in thesafe position unless the `hammer be cocked.

The barrel illustrated is six and three-eighths inches in length and isbored for about 35 caliber.

When the pin |81 is removed, the barrel-receiver may be slid free of thegrip member G. The slide, action spring, pilot rod and breech bolt slideout of the barrel-receiver towards the open rear. The pistol of Figs. 13to 21 is of Very simple construction being formed by the simplestmachining operations.

Figs. 22 to 26 illustrate only theupper part of the grip member G, itbeing understood that the lower part thereof may be similar to-thatshown in Fig. l or 13. The barrel-receiverhas a cylindrical space abovethe bore and extending from end to end in which is mounted thecylindrical slide |9|. The barrel is deep and narrow in cross-sectionhaving an oblong configuration similar to the barrels of Figs. 1 and 13.The fore ward end of the space is closed bya screwplug |92 yand connectsto the bore by a gas duct |93.

The upward extension 94 on the frame 195 oi the grip member has acylindrical projection 96 which lits into the cylindrical chamber lillin the receiver and in line with the bore, and the rear end of thebarrel-receiver is thereby slidably coupled to the grip member. Thefront part of the grip member is slidably connected to the bar-- rel bythe wedgeshaped lug 5% which slides into a wedge-shaped slot similar tothat oi Fig. 8 and the two members are secured together by the pin 200.

The slide i9! has a central cylindrical space 20! a part of which isfilled with lead 2li-2 to increase its mass and has a screw plug 293with a cylindrical hole in which the combined action rod and pilot rod20e is slidable. The rod slides through a hole 205 in the extension E06and is threaded into the manual operating member The other end of therod has a head Ztl slidable inside the space ZEM. The action spring Zlllbears against the extension |94 at one end and the plug 203 at the otherend. Member 2% guide rails 209 and 2li! securely attached thereto as bythreads. These rails pass through holes in the extension Edil and member266 is thereby held in its upright position and is prevented fromturning.

The slide has a depending lug 2l l which oper ates in a helical cam slot2HE in breech bolt 253 similar to that of Fig. 20. The metal betweencylinders Mill and lill is cut out to form the guideway 2M in which thelug 2li travels, pr.,w venting the piston slide 20| from turning. Thelocking lug M5 also travels in this guideway when the bolt reciprocates.In this form of the invention the bolt has two locking lugs and groovestherefore which are similar to those shown in Fie.. 20 and the extractor23S may be of any suitable type.

One of the features of the pistol of Figs. 22 to The side of themagazine 22e has a slit 22'! near the corner and another slit 228 spacedinwardly therefrom, leaving a section 229 as a fairly easily movableflap. As shown in Figs. 24 and 26 the projection. 235i presses the flap229 inward under the strong turning action of spring 22d. When the catchis in the position shown in Figs. 24 and 26, the lug 23! is swung infront of the bolt 253 and the bolt is locked in its open position. Thebolt may be released by pressing the opposite outwardly projecting end232 inward.

Normally. whether the magazine be loaded or empty, the flap lies iiushwith the side of the magazine and when itis loaded the cartridgesprevent it being pushed inward by the catch lug When the last cartridgehas been removed from the magazine and when the bolt has moved to itsrearward position, the spring 22d pushes the catch inward as describeduntil the catch lug 23! takes position in front of the bolt and blocksit from closing. rThis action of the catch is possible because the flapyields permitting the catch 222 to be pivoted. The catch not only holdsthe bolt open when the last shot has been red but it holds the holt openeven when the magazine is not used. The pistol may be used for singleshot ring and the bolt automatically remains open after each shot withor without the magazine.

When a cartridge is red and the bullet goes past port its, gas passestherethrough into cylinder i9@ and drives the slide l 0l rearwardagainst action spring 263, the lug 2i l operating in the cam groove i?!2 to operate the bolt in the manner described in connection with Figs.i3 to 21. The manual operating member 2525 and rod 204 remain stationarydue to their inertia and frictional resistance and the slide moves overthe rod. When it is desired to operate the breech bolt 213 manually, themember is pulled backward and the head 'Ztl engages the plug 2&3 anddraws the slide and bolt rearward. When the motion has been completedthe member 230 may be released and the action spring Zilli drives theslide and breech bolt forward to the locked position.

As stated hereinbefore, an important feature of the invention is theproportioning and arranging of the operating elements of the pistol tohave more of the mass of the pistol above the bore plane than below. 1tis necessary to eliminate all unnecessary weight below the bore plane.This may be accomplished by cutting out all unnecessary weight in thegrip member, especially when the grip member frame is made of a heavymetal like steel. Since the grip member of the invention is under verylittle strain no heavy sections are necessary.

In determining the weight of the pistol above and below the bore planethe magazine is removed and the barrel chamber is emptied. The hammer isset in position against the ring pin, the position it occupies at thetime of ring. The pistol may have such excess weight above that itovercomes the weight of the magazine. I have found that the rst shotfrom a fully loaded automatic does not strike the same place as the lastshot, when the magazine is empty and that the moet consistent accurateshooting slow re will be accomplished when the magazine is removed. Thepistol, nevertheless, operates automatically especially in unloading,and the term autoloading as used herein covers both loading andunloading.

The formation of the grip member frame of a light cast or moldedmaterial gives distinct advantages in the way of low weight and lowcost. lt may be cast of aluminum or the low-silicon aluminum alloyssimilar to the engine piston alloys, or of magnesium alloys containingsay, from 0.05 to 3 percent manganese, or the magnesium base alloyscontaining from 0.1 to 12 percent of aluminum and from 0.05 to 1 percentof manganese. When the grip member frame is cast from a light metal themechanical operations are reduced to a minimum and are comparativelysimple. The trigger and parts of the magazine and magazine catch as wellas certain screws and parts of the safety may be made of such metals.

The grip member frame may be molded from resins such as vinyl, phenolic,or methacrylates. The thermosetting resin having the trade name Toolitehas distinct advantages because of its light weight and high compressivestrength of around 20,000 pounds per square inch. Moreover, it may becast to very accurate dimensions.

In view of the simple mechanical operations required to form thebarrel-receiver, it may be made of stainless or other corrosionresistant steel the use of a plastic or light metal grip member framegives a pistol adaptable for use in damp climates.

The slide of Fig. 22 is weighted with lead and 'it is to 'befunderstoodthat the slides of theother embodiments of the invention may be weightedwith lead, depending on'the caliber, length of barrel and diameter ofthepiston.

I claim:

1, An autoloading pistol comprising a receiver, a barrel connected tothe receiver, said barrel being oblong in vertical direction incross-section,

`a grip member for the barrel and receiver having a space in the gripfor a cartridge magazine, a breech bolt in the receiver, means forlocking and unlocking the breech bolt in breech closing position withrespect to the barrel, said means including a longitudinal space in thereceiver and in the barrel above the bore extending from the Vrear ofthe receiver through the barrel, apart of a barrel connected .to thereceiver, said barrel being oblong in vertical direction incross-section, a grip member for the barrel and receiver having a spacein the grip for a cartridge magazine, a breech bolt in the receiver,means for locking and 4 unlocking the breech bolt in breech closingposition with respectto the barrel, said means including a longitudinalspace in the receiver and vin the barrel above the bore extending fromthe rear ofthe receiver through at least the major portion of thebarrel, a .part of the space in the barrelbeing a cylinder, a pistonmounted in the cylinder, meansV extending rearwardly from and:operatively connecting the piston to the breech Jbolt, a gas ductconnecting the bore with the cylinder `forward of theA piston to admitgas from the bore to drive the .piston rearwardly to unlock and move the`breech bolt rearwardly and eject the empty case, and means for forcingthe breech bolt `and piston forwardly to vlocked breech closingposition, the parts comprising the pistol being so proportioned andarranged that the mass above the bore plane is at least equal to themass -below the bore plane.

"3. -An autoloading pistol according to claim 1 in which the space inthe barrel above the bore extends completely through the barrel and aremovable plug in the space closing it at the muzzle end forward ofthegas port.

4. An autoloading pistol comprising a receiver, a barrel connected tothe receiver, said barrelbe ing oblong inL vertical direction in-cross.section, a grip member for thez barrel and receiverhaving a space`in the grip for` acartridge magazine, a 'breech bolt inthe receiver,means :for locking `and unlocking the breech bolt in breech closing posit-ion with respect to the barrel, said means llncluding a`longitudinal space in the receiver and in the barrel above the boreextending from the rear of the receiver into the barrel, a part of the.space in the ybarrel being a cylinder., a. piston mountedrin thecylinder, means extending rear- :Wardly from and operatively yconnectingthe piston to *the breech bolt, a gas duct connecting the bore with thecylinder forward of the piston Vto admit gas from the bore to drive thepiston rearbreech clos-ing position, a rear sight mounted on thereceiver, and a -f-ron-t sightA mounted onfthe barrel, said sights beingyboth rigid and fixed with respect to the bore and immovable byactuating parts of the pistol.

HAL E. SEAGRAVES.

REFERENCES CITED The following references are of record in lthe 'file of`this patent:

Number Name Date 570,388 'Ehbets Oct. 27, 1896 580,923 l'Browning Apr;20, 1897 1813,694 'Fidgeland Feb. 27, `1906 934,158 Gates Sept. 14, 1909944,606 Frommer Dec. 28,` 1909 992,854 Cobb zMay 23, 1911 1,041,928vWesson '.Oct. 22,I 1912 1,163,516 Du-iTek EDec; 7, 1915 1,166,554 SmithJan; 4,*19'16 1,291,690 Smith Jan'. 14, 1919 1,344,991 Cunningham June29, 1920 1,387,460 Beet-s Aug. 16, 1921 i 1,388,856 Fox Aug. 30, 19211,430,662 Lewis Oct., 3, 1922 1,511,509 Diehm Oct. 14, '1924 1,520,671Rosier Dec. I23, 1924 1,711,874 Brinkerhoff May 7, 1929 1,759,277Revelli May v20, 1930 `1,835,286 Dickinson Dec. 8, 1931 2,088,268 LaufJuly 27, 1937 2,287,032 -Garand June 23, 1942

